Re: [Gomp-discuss] Organization of libgomp source code

[Steven Bosscher]

Op di 18-02-2003, om 12:14 schreef Biagio Lucini:
> On 18 Feb 2003, Steven Bosscher wrote:
> 
> > It doesn't work right now because you need to set library properties
> > that we had not defined yet (e.g. these is no omp_num_threads variable
> > yet).  Also the schedule environment variable isn't implemented yet. 
> > Also, reading the environment should somehow just be part of the library
> > initialization.
> > 
> > So, it was just an example of how it *could* be done.  It's quite easy
> > to actually make it work, though.
> > 
> 
> Thanks, Steven. As soon as I have some time (!!!) I'll try and modify it.
> I think the strategy should be
> a) define the OpenMP environment (you did it)
> b) set our default (or is there any OpenMP spec for that?)
> c) read the enviro & overwrite the default
> d) pass the enviro structure to all OpenMP functions as required (then I
> guess it must be declared as extern?)
> e) overwrite it locally when a library function does it.

I was more thinking:
a) At startup (initialization), read the environment, and
   set the default if the environment variable is not set.
b) The omp_set_num_threads () (?) function can adjust the
   default at runtime.
c) Use the clause value for the OpenMP functions as required.
   If the clause is absent, the compiler sets the num_threads
   value to, say, -1, and the functions use the default.

So, the defaults are global variables, and there is a local value for
each parallel region, which is either the default, or the number from
the num_threads clause.

Greetz
Steven